Emulation of conducted emissions of an automotive inverter for filter development in HV networks

At present, electric traction systems are introduced into automotive applications. The driving power is transmitted via cables, which are routed close to various communication, sensor or control units. Ensuring the electromagnetic compatibility (EMC) of these miscellaneous systems within the electric vehicle is a new challenge for the developing engineers. Line filters are a very effective EMC measure, but a time-consuming and ineffective trial-and-error approach can only be avoided if the input and output impedances of the filters are characterized and known. This paper characterizes the impedance situation for a line filter within a high voltage traction system. It is intended to reduce the conducted emissions of a power inverter for a hybrid driven car. Therefore, the inverter´s common and differential mode input impedances are determined. The tested device is modeled as a voltage source combined with an inverter emulating network of concentrated elements. Verifying measurements show that the inverter´s EMC performance can be reproduced with the presented inverter emulation. The influence of the changed impedance situation on the attenuation of a first-order low-pass filter is shown by emission measurements.